Hitherto, there has been used the so called bias tire as a tire for high loads such as tires for industrial vehicles, construction vehicles and the like, but recently, a radial tire in which steel cords are embedded in its carcass is most popular because it excels in ride comfort and wear resistance.
However, such radial tire has a low vertical spring coefficient. Therefore, especially when it is applied to forklifts which have many opportunities for turning, starting and stopping, rolling and pitching of the vehicle tend to occur. Also at the time of driving, when the tires run over projections or obstacles on the road, it gives the vehicle body unstable rolling properties. This becomes a problem, if steel radial tires with conventional structure are used on industrial vehicles, such as the forklifts or high place working vehicles, because they become a factor in the vibration of the mast or the crane thereof, whereas if applied to the passenger cars this presents no problem.
Ways of reinforcing the carcass of the radial tire have been studied, particularly the portions in the tire sidewalls which are largely bent, and the matters by which the vibration damping performance is improved has been investigated, throughly, thereby arriving at the completion of the present invention.